The present invention relates to recuperative heat exchangers, and more particularly, to tubular heat exchangers of the type wherein a heating fluid is passed over a plurality laterally adjacent heat exchange modules arranged in a box-like array, with each module housing a plurality of heat exchange tubes through which a fluid to be heated is passed in heat exchange relationship with the heating fluid.
In a typical recuperative heat exchanger of the type to which the invention pertains, a number of heat exchange modules are disposed in a box-like array, laterally adjacent to each other. Each heat exchange module comprises a plurality of longitudinally disposed tubes mounted at their opposite ends to apertured tube sheets. The fluid to be heated passes through the heat exchange tubes of the modules in heat exchange relationship with the heating fluid which is being passed through the array of heat exchange modules in cross flow over the outside of the heat exchange tubes.
A major advantage of the modular concept of construction for recuperative heat exchangers lies in the simplified field erection associated with the modular construction. Recuperative heat exchangers are generally rather large structures often having a height of more than ten meters and a width of more than fifteen meters. To field erect such a structure from scratch is a very labor extensive, time-consuming task and, therefore, costly. By constructing a recuperative heat exchanger of pre-assembled, shippable modules, both field erection and transportation are simplified and costs reduced.
Typical prior art modular tubular heat exchangers of the recuperative type are exemplified by the heat exchangers of U.S. Pat. Nos. 2,487,626; 2,653,799 and 4,202,407. Each of these heat exchangers is formed of a plurality of tubular heat exchange modules disposed in a stacked array of one or more columns. Each individual module is comprised of a plurality of longitudinally disposed tubes extending between and mounted to a pair of spaced tube sheets. Laterally adjacent modules are attached to each other by securing their flanged tube sheets together by bolting, pinning or welding. In each case, the tube sheets of the individual modules in the array are linked together to form the support structure of the heat exchanger. Therefore, it is difficult to remove any single module for service or replacement without jeopardizing the structural integrity of the remaining structure.
Accordingly, it is an object of the present invention to provide an improved modular tubular heat exchanger whereby the removal of individual tube bundles may be accomplished without effecting the structural integrity of the heat exchanger.
It is an additional object of the present invention to provide a tubular heat exchange module whose construction facilitates shipment, field erection, and field servicing.